Method for the removal of organic residues from finely structured surfaces

ABSTRACT

Method for removing of organic residues from finely structured surfaces, in which the residues are incinerated by ozone.

The invention relates to a method for removing of organic residues fromfinely structured surfaces.

As an example, reference shall be made to the removing of photo resistlacquer residues from metallic injection moulding matrices forManufacturing of CD or DVD discs, but the Invention shall not be limitedto this method.

When manufacturing CD's or DVD's, first a photo resist lacquer layer isapplied onto a glass pane. This lacquer layer is dried. It is afterwardsexposed in accordance with the digitally displayed sound pattern andwashed out in the areas determined by the exposure. Then a thinelectrically conductive layer of metal, e.g. nickel, is applied byevaporating in an electric field onto the lacquer layer, and afterwardsa 300 μm thick metal layer is applied onto the thin metal layer,particularly nickel layer, as a starting layer by a galvanic method.

The metal layer produced by this method is used during the furtherproceedings as injection moulding mould for manufacturing of CD's andDVD's. For this purpose the metal layer must be peeled from the photoresist lacquer layer. In this connection, substantial parts of thelacquer layer remain on the metal plate. It is rather easy to remove theresidues to a great deal by a suitable pre-cleaning step. In the boarderlayer between metal and photo resist lacquer however, there is formed astrongly cross linked photo resist lacquer by the method which isdifficult to remove in the finely structured surface of the metal plate.

A removal of these residues by means of solvents is known in the art butonly leads to non-satisfactory results. More effective but alsosubstantially more complicated is cleaning by means of plasma burners orexcimer lasers.

These methods have the disadvantage that they require high investmentand operational costs and that they can be used only in a very narrowfield if it is to be reliably prevented that the basic substrate, In thepresent example the metal plate is damaged.

It is the object of the invention to provide a method by which it ispossible to incinerate the organic residues remaining on or in a finelystructured surface with a low demand of investment and operationalcosts.

To comply with this object, the above method according to the inventionis characterized in that the residues are incinerated by means of ozone.

It turned out surprisingly that the strongly oxidizing effect of theozone is sufficient to remove organic residues from the finelystructured surface without damaging the surface structure.

The ozone may be blown onto the surface to be cleaned by means of atleast one nozzle. One or a plurality of nozzles may be guided alongpredetermined pathes over the surface, or the surface may be moved alongone or a plurality of nozzles. It is also possible to put the parts tobe cleaned into an ozone chamber wherein ozone in a predeterminedconcentration exists,

The ash components may be removed by suction, blowing or washing bymeans of a suitable rinsing device without difficulties.

The ozone may be provided by a relatively simple ozone generator inplace which Is causing an electrostatic discharge. By means of an ozonegenerator of this kind it is possible to provide a great volume of ozoneat low costs. This allows short treating times.

Methods using the ozone production by means of UV-light are obviouslyless favourable. In this case the ozone output is comparatively small,and the resulting heat is not favourable for the result to be obtained.

1. Method for removing of organic residues from finely structuredsurfaces, comprising the step of incinerating the residues ozone. 2.Method as claimed in claim 1, further comprising the step of blowing theozone onto the surface to be cleaned by at least one nozzle.
 3. Methodas claimed in claim 2, further comprising the step of moving the atleast one nozzle over the surface to be cleaned in predetermined paths.4. Method as claimed in claim 2, further comprising the step of passingthe surface to be cleaned along the at least one nozzle. 5-8. (canceled)9. Method as claimed in claim 1, further comprising the step of suckingthe incinerated residues from the surface.
 10. Method as claimed inclaim 1, further comprising the step of blowing the incinerated residuesfrom the surface.
 11. Method as claimed in claim 1, further comprisingthe step of rinsing out the incinerated residues by a cleaning solution.12. Method as claimed in claim 1, further comprising the step ofproducing the ozone during the cleaning process by an ozone generator.